Intracameral muramyl dipeptide-induced paracellular permeability associated with decreased glutamate transporter and gamma -glutamyltranspeptidase activities.

Muramyl dipeptide (MDP) (N -acetylmuramyl- L -alanyl- D - isoglutamine) was injected intracamerally to test if MDP applied to the aqueous side of the blood-aqueous barrier would increase paracellular permeability in association with diminished uptake of glutamate. The symptoms of anterior uveitis, i.e., increase in vascular dilatation, could be detected as early as 30 min post MDP injection while aqueous protein concentration did not increase at this time suggesting an initial dissociation between the circulatory and epithelial barrier responses. However, at 45 min, the aqueous protein concentration increased 10-fold (201+/-174 to 2094+/-1835 micrograms ml-1;P<0.001) rising progressively to 20-fold above the control eye at 60 min post injection (254+/-194 vs. 5038+/-2514 micrograms ml-1;P<0.001). Epithelial cell barrier paracellular permeability increased at 45 min as evidenced by the enhanced efflux of radiolabelled L -glucose out of the aqueous (8% and 13% faster than control at 45 and 60 min post MDP injection, respectively), coinciding with the accelerated protein influx. A near 50% reduction in efflux of both radiolabelled glutamate and D -aspartate was consistent with reduced glutamate uptake by the transport system X-AG. In addition, a 24% decline in aqueous glutamate, but not aspartate, was detected in the aqueous of the MDP-treated eyes in association with a 54% decrease in iris/ciliary body gamma-glutamyltranspeptidase activity consistent with reduced de novo glutamate formation from glutamine. The aqueous of MDP injected eyes also had 6-fold and 34-fold higher prostaglandin E2and F2alphaconcentrations, respectively (P

Epidemiologic study of time and space clustering of 4 cases of choroidal malignant melanoma.

OBJECTIVE: To identify common risk factors that might be associated with a cluster of 4 cases of choroidal malignant melanoma that occurred in a manufacturing plant between 1982 and 1985. DESIGN: Survey of choroidal malignant melanoma cases in Caddo and Bossier parishes during the same time frame. METHODS: We identified 4 additional individuals with choroidal malignant melanoma first diagnosed during the study period. Characteristics of the workplace were examined and a questionnaire was administered to all subjects to ascertain exposures to putative carcinogens and to putative risk factors for intraocular malignant melanoma. Observed and expected incidence rates were calculated. RESULTS: The overall incidence of intraocular malignant melanoma for the 2 parishes during the 4-year period was 0.56 cases per 100,000 population per year, similar to the expected rates for this population. The incidence rate for the manufacturing plant employees was 16.5 cases per 100,000 per year. The mean age at diagnosis for workers at the plant was 38.7 years compared with 69.2 years for nonplant employees. CONCLUSIONS: The close occurrence of manufacturing plant cases in time and space and the younger age of the people are consistent with a cluster of intraocular melanoma cases. No specific risk factors were found in the workplace environment to impute a causal association.

Inhibition of glutamate uptake causes an acute increase in aqueous humor protein.

Inhibition of glutamate transport has been shown to increase paracellular permeability of epithelial cell monolayers in vitro. To determine if blocking glutamate transport would affect tissue permeability in vivo, D-aspartate (D-Asp; 300 nmol 30 microliters-1) (a non-toxic competitive inhibitor of glutamate transport) or a placebo was injected into the anterior chambers of the fellow eyes of 15 adult rabbits. [14C]-L-glucose and/or [125I]-rabbit albumin were included in the injection vehicle as aqueous humor (AH) outflow markers. The specific inhibition of glutamate uptake by D-Asp was indicated by a 15% increase in AH glutamate (174 +/- 9 nmol ml-1 to 205 +/- 13 nmol ml-1; P = 0.03) at 1-1.5 hr post injection. Also, the efflux of [14C]-L-glucose and [125I]-rabbit albumin from the AH of D-Asp injected eyes was increased 22% over the placebo-injected control eyes (P < or = 0.02). Concomitantly, the total protein concentration in the AH from D-Asp injected eyes (517 +/- 35 micrograms ml-1) was 19% greater (P < 0.02) than the protein concentration in AH from placebo-injected control eyes (420 +/- 36 micrograms ml-1). In additional studies, an irreversible inhibitor of glutamate transport, threo-beta-hydroxyaspartate (THA; 30 nmol 30 microliters-1), was shown to increase the efflux of [14C]-L-glucose (22%; P < 0.05) from the anterior chamber and increase AH protein concentrations by 29% (484 +/- 112 micrograms ml-1 in control AH versus 686 +/- 117 micrograms ml-1 in THA AH, P = 0.08) at 1 hr post intracameral injection. SDS-PAGE analysis of the AH associated the protein increase in the D-Asp and THA injected eyes but not placebo-injected control eyes with a detectable increase in a 66 kDa protein (aligns with serum albumin) and several lower molecular weight (23-35 kDa) AH proteins. The results found suggest that inhibition of glutamate transport from the AH acutely increases intraocular epithelial/endothelial paracellular permeability.

Projected color slides as a method for mass screening of red-green color deficient individuals.

University students (111, both male and female) were screened for red-green color deficiency using projected 35 mm slides reproduced from Ishihara and H-R-R color plates. Ishihara and H-R-R color plates were tested in the same individuals at a second setting and the responses compared: 6.3% of the students were identified as color deficient by the Ishihara and 80.2% by the H-R-R projected slides while 5.4% were designated color blind by the Ishihara plates and 4.5% by the H-R-R plates. The sensitivity of both screening systems was 100%; the specificity of the Ishihara slides was 98.1% compared to only 20.8% for the H-R-R. The 9.8% prevalence of red-green deficiency detected by the Ishihara plates and 8.2% by the H-R-R plates for males is similar to the 6 to 9% frequency found for Caucasian males in other population studies. Within rigid guidelines, projected color slides have potential usefulness as a screening method for detecting individuals with red-green color deficiencies.

Temporal association of interferon-alpha and p27 core antigen levels in sera of simian immunodeficiency virus infected monkeys.

We report the temporal association of interferon (IFN) and p27 core antigen production during experimental simian immunodeficiency virus Delta B670 (SIV) infection in rhesus monkeys. Peak serum IFN-alpha levels (10(2.8-5.0)U/ml) occurred 10 days post infection (p.i.) and peak p27 levels (3.1-34.4 ng/ml) occurred 10-14 days p.i. Acid-stable IFN-alpha (10(1.6-2.5)U/ml) was detected 3-5 days before p27 in sera from three monkeys and was detected with p27 (0.06-3.06 ng/ml) in four monkeys during the primary infection. Serum IFN-alpha and p27 levels became undetectable 24-40 days p.i. Two monkeys remained asymptomatic for SIV after the primary p27 antigenaemia, three monkeys had recrudescent (3-4 months p.i.) acid stable interferonaemias (10(1-2.5)U/ml) with p27 antigenaemias (0.06-2.7 ng/ml) that persisted until death, and two monkeys had acute SIV infections (died < or = 7 months p.i.) with persistent acid-stable interferonaemia (10(1.6-2.5)U/ml) and p27 antigenaemia (6-9 ng/ml). Our results indicate that the detection of acid-stable IFN-alpha in serum is closely associated with detection of p27 (P = 0.0001) and suggest that detection of acid-stable IFN-alpha and p27 core antigen is indicative of active SIV infection.

Inhibition of the enteroviruses that cause acute hemorrhagic conjunctivitis (AHC) by benzimidazoles; enviroxime (LY 122772) and enviradone (LY 127123).

Enviradone (EvirD, (E)-1-[(1-methylethyl) sulfonyl]-6-(1-phenyl-1-propenyl)-1 H- benzimidazole-2-amine) and Enviroxime (EvirX, 2-amino-1-(isopropyl-sulfonyl)-6-benzimidazole phenyl ketone oxime) inhibited enterovirus 70 (EV70) and coxsackievirus A24 variant (CA24v) infection of conjunctival and laryngeal cells. On average, the continuous presence of 1-3 micrograms of EvirD or EvirX/ml in cell cultures acutely infected with EV70 or CA24v inhibited virus production (> 2 log10 reduction) and 100% of the viral cytopathogenic effect (CPE). The 50% CPE inhibitory dose (ID50) for EvirD and EvirX against 11 EV70 and 15 CA24v isolates ranged from 0.01 to 0.3 microgram and 0.01-0.65 microgram/ml, respectively. The mean ID50 for EvirD and EvirX against the 26 AHC viruses was 0.17 +/- 0.12 microgram and 0.13 +/- 0.14 microgram/ml, respectively. Pretreatment for 15 min with 3 micrograms EvirX/ml or for 1-2 h with 3 micrograms EvirD/ml protected conjunctival cells against viral CPE. The cells were resistant to infection for 1-2 h at 33 and 37 degrees C after removal of EvirD and EvirX. The addition of 10 micrograms EvirD/ml up to 6 h or 10 micrograms EvirX/ml 1-2 h after low multiplicity infection inhibited viral CPE. Ten-fold less EvirD inhibited EV70 when added to glioma cells 2 h before infection than when added 2 h after infection. Our results indicate that EvirX and EvirD inhibit AHC viruses in vitro at concentrations that are not cytotoxic and suggest that EvirX or EvirD may be prove useful against AHC.

Non-neoplastic chorioretinal enhancement patterns in magnetic resonance imaging of the eye.

OBJECTIVE: To define the role of contrast-enhanced magnetic resonance imaging (MRI) as a possible adjunct to funduscopy and ultrasonography in a selected sample of non-neoplastic disorders of the chorioretina. PATIENTS AND METHODS: The study group consisted of five patients (ranging in age from 3 to 78 years) with one of the following diagnoses: ocular toxocariasis, staphyloma, glaucoma, or ocular involvement of cytomegalovirus (CMV) infection or AIDS. All of the patients underwent MRI, and the findings were correlated with those of funduscopy and ultrasonography when possible. RESULTS: There were two abnormal MRI enhancement patterns, one with and the other without major distortion of the chorioretina. Areas of abnormal enhancement correlated well with the funduscopic findings. For the patient with CMV infection and the one with AIDS, who were not examined with ultrasonography, MRI showed subtle chorioretinal abnormalities. In the other three cases, for which both ultrasonography and MRI were performed, the findings of the two methods correlated well. CONCLUSIONS: Ultrasonography remains the imaging modality of choice in the work-up of most ocular abnormalities. Ultrasonography, MRI and computed tomography are recommended when funduscopy is technically not possible. Because contrast-enhanced MRI is often performed to define the remainder of the orbit, as well as extra-orbital structures, and because of its capability to demonstrate abnormalities of the chorioretina, this modality may serve as a useful adjunct to ultrasonography. Further studies are needed to compare the efficacy of contrast-enhanced MRI and ultrasonography in the evaluation of small, nonneoplastic lesions of the chorioretina.

Risk of visual impairment attributable to ocular histoplasmosis. Washington County Follow-up Eye Study Group.

PURPOSE: To compare 15-year incidence rates of visual impairment and vision-threatening conditions between cases with ocular histoplasmosis and controls residing in the same endemic community. METHODS: Controls and cases with and without disciform lesions who were between 30 and 69 years of age when selected, interviewed, and examined in 1970 were reinterviewed and reexamined in 1985. RESULTS: Of the 252 cases and controls examined in 1970, 216 were still alive in 1985. Of these, 202 (94%) were interviewed; 197 (91%) underwent visual acuity measurement; and 173 (80%) were examined by a study ophthalmologist. Both in 1970 and in 1985, cases with disciform macular lesions of ocular histoplasmosis had a higher prevalence of both unilateral and bilateral visual impairment and blindness. Although prevalence of visual impairment and blindness in 1985 was similar among controls and cases of ocular histoplasmosis without disciform lesions, this group of cases had about twice the incidence of visual impairment as that of controls. However, the 95% confidence intervals on estimates of relative risks were broad and included unity. No new disciform lesions attributable to ocular histoplasmosis were found in 28 eyes of 18 cases free of them in 1970 or among 148 controls. CONCLUSIONS: The 15-year risk of visual impairment and blindness appears to be somewhat higher among adults aged 30 years and older who have only peripheral atrophic scars characteristic of ocular histoplasmosis than among individuals without such scars who live in the same endemic community. Adults who already have a disciform lesion attributed to ocular histoplasmosis in one eye are at low risk of development of a disciform lesion in the fellow eye later in life.

The hopscotch position. A screening test.

The author discusses an examination method that is performed in a matter of seconds by either the physician or the parent. When the child is placed in a specific "hopscotch" position, otherwise obscure leg and foot deformities become readily apparent, and early treatment is then made possible.

Cytopathogenicity, drug susceptibility, and thymidine kinase activity of a retinovirulent herpes simplex virus type 2.

We investigated some of the biological and biochemical characteristics of a neuroinvasive, retinovirulent herpes simplex virus type 2 strain SL (HSV-2[SL]) and compared them with those of a neurovirulent, nonretinovirulent HSV-2 (186). HSV-2(SL) was shown to spread rapidly and produce large syncytium in vitro. HSV-2(SL) and HSV-2(186) were equally susceptible to acyclovir (ACV) and thymine arabinoside (Ara-T). However, HSV-2(SL) was fourfold and 44-fold more susceptible than HSV-2(186) to iododeoxyuridine (IUdR) and bromovinyldeoxyuridine (BVDU), respectively. In addition, cytosolic TK from HSV-2(SL)-infected cells phosphorylated 4, 20, and 23,000 times more IUdR, iododeoxycytidine (IdCyD), and Ara-T than the TK of HSV-2(186), respectively. Further, HSV-2(186) TK did not phosphorylate Ara-T, but HSV-2(186) replication was inhibited by Ara-T. These studies indicate that the retinovirulent HSV-2(SL) has a syn phenotype and a TK with broad substrate activity.

Isolation of a herpes simplex virus type 2 that is retinovirulent in mice.

The virulence of a herpes simplex virus type 2 (HSV-2) isolated from the urine of a patient (SL) with acquired immunodeficiency syndrome (AIDS) and bilateral acute retinal necrosis (ARN), was investigated in mice. The ratio of plaque forming units (PFU) in fibroblasts to the 50% lethal dose (LD50) of HSV-2(SL) in mice was 10 fold more than the PFU to LD50 ratio of a neurovirulent HSV-2, strain 186. Further, HSV-2(SL) caused retinitis with and without lethal encephalitis in mice inoculated intracranially (i.c.). In contrast, mice inoculated with HSV-2(186) died of encephalitis without ocular disease. HSV-2(SL) was isolated from eye and/or brain tissue 1 to 15 days post i.c. inoculation. Ocular disease progressed from an initial mild chorioretinitis on day 8 to total retinal necrosis with panuveitis by day 11 in mice given 10 PFU of HSV-2(SL) i.c. HSV antigen was detected initially in the cells of the optic nerve and spread into the ganglial cells of the nerve fiber layer, the neurosensory cells of the inner nuclear layer, and the cells of the retinal pigment epithelium (RPE) between days 8 and 10. Thus, this study supports the concept that HSV neurovirulence varies between strains and presents a HSV-2 neurotransmission animal model of ARN.

Inhibition of epidemic isolates of coxsackievirus type A 24 by recombinant and natural interferon alpha and interferon beta.

Natural human interferons (IFN) and recombinant human IFNs (rIFN-alpha and rIFN-beta) inhibited the production of virus in Chang's human conjunctival cell cultures infected with epidemic isolates of acute hemorrhagic conjunctivitis virus, Coxsackievirus type A 24 (CA24). Generally, natural and rIFN-alpha and rIFN-beta were equally effective in inhibiting CA24 infection. However, rIFN-alpha A was more effective than rIFN-alpha C, D, I, J, and K in reducing virus infection, cytopathogenesis, and virus production. Recombinant IFN-alpha J was least effective in inhibiting CA24 in human conjunctival cell cultures. Also, the IFN titer was reduced 10- to 1,000-fold when cells were infected with greater than or equal to 0.3-0.5 CA24/cell, suggesting a dose-dependent IFN resistance by CA24. These results suggest that the antiviral activity of IFN against acute hemorrhagic conjunctivitis in vivo may vary with the CA24 isolates, the MOI, the type of IFN, and the time of infection with respect to beginning IFN treatment.